Non-woven fabrics are used in the manufacture of products such as washing and wiping cloths, diapers, sanitary napkin covers, hospital gowns, surgical drapes, sheets, pillow cases, curtains, backing material for garments, table cloths, bed spreads, sponges, underpads, etc. For these products and products such as sheets, pillow cases, hospital gowns and surgical drapes in particular, it is highly desirable to render the non-woven textiles or other non-woven type materials antimicrobial and/or antiviral. Indeed, the passage of liquid through surgical drapes, which are used during surgical procedures to isolate the patient from the operating room personnel and environment, is one source of bacterial contamination to the patient.
Similarly, rendering woven fabrics and fleece antimicrobial or antiviral is also advantageous.
Conventionally, harsh chemicals are required to provide antimicrobial effects. For example, a normal disinfectant solution of 0.15% to 2% glutaraldehyde is required to kill microorganisms and viruses on surfaces being cleaned, and the exposure time required is from 3 to 18 hours. Glutaraldehyde is corrosive, is a sensitizer and harmful if inhaled, absorbed through the skin or swallowed. Indeed, the OSHA personal exposure limit to glutaraldehyde is 0.2 ppm. Similarly, although chlorinated water disinfecting solutions such as sodium hypochlorite and chlorinated H.sub.2 O kill most microorganisms and some viruses including HIV in seconds to minutes, depending upon the concentration, the activity of chlorinated water is reduced by organic material and some metallic catalysts. Hydrogen peroxide solutions kill, but have no long term effect; they are quickly inactivated by organic materials with which they react. Iodine in high concentration in solution will kill most microorganisms and some viruses, however, it has an irritating odor and residue except with Iodophors. Alcohols are the most effective and frequently used agents for sterilization and disinfection, but are flammable in concentrations required for effectiveness. Phenols are frequently used with halogens and detergents as a general disinfectant for toilets, stables, cesspools, floors, drains, and other surfaces, but they are harmful to tissues in high concentration and they have a disagreeable odor. Detergents in combination with quaternary ammonium compounds are widely used to kill bacteria in hospitals, restaurants, and in food processing plants, however, they may not kill some viruses and their effectiveness is reduced by hard water and fibrous materials. Heavy metals are used to kill some bacteria and viruses, but they are ineffective against tuberculosis and are inactivated by organic compounds. Although boiling kills microorganisms, it is not practical for many objects that must remain dry or cannot handle the high temperature for the 15 to 20 minutes required to kill microorganisms.
Light-activated dyes are known to exhibit antimicrobial activity in water. However, they are not necessarily effective in the dry state or when bound in a polymeric system. For surgical drape applications in particular, the cellulosic material and other additives necessary for a fenestration place demands on the binder. A satisfactory product must have a dye bound to a cellulosic non-woven material lightly enough to be effective, yet tightly enough to avoid excessive leaching. More specifically, the light-activated dye must be incorporated into the substrate such that it retains its light-activatable property yet does not leach significantly therefrom.
The prior art includes disclosures of nonwoven materials rendered antimicrobial. For example, European Patent Application 0 136 900 discloses a nonwoven fabric having antimicrobial properties suitable for use as a surgical drape. The surgical drape is made with a cellulose-containing, nonwoven fabric that is bonded with a binding agent which contains little or no anionic surfactant or is made with a nonionic surfactant, such as a copolymer of ethylene and vinyl acetate, and polyhexamethylene biguanide salt as the antimicrobial.
Similarly, U.S. Pat. No. 5,069,907 discloses a surgical drape comprising a synthetic polymeric film such as polyethylene or polyurethane, and an antimicrobial agent such as 5-chloro-2-(2,4-dichlorophenoxy)phenol incorporated throughout the film. Also disclosed are surgical drapes comprising fabric forming material to which the antimicrobial agent is directly added prior to forming the material into a drape.
U.S. Pat. No. 4,643,181 discloses surgical dressings and incise drapes having an adhesive surface, the adhesive containing a salt of polyhexamethylene biguanide as an antimicrobial agent.
U.S. Pat. No. 4,721,511 discloses a leach resistant antimicrobial fabric, wherein the antimicrobial agent is a silane quaternary amine such as 3-(trimethoxysilyl)-propyloctadecyl-dimethyl ammonium chloride.
However, the prior art does not disclose a substrate having bound to it a light-activatable dye to obtain antimicrobial and/or antiviral effects. It is therefore an object of this invention to provide such a substrate.